Bessler's Wheels.

Illustration from Bessler's pamphlet of 1715, before the Weissenstein wheel was constructed. (The high resolution picture may be slow to load.)

Two views of Bessler's wheel. Edge view at left. Face view at right. This wheel was about 12 feet in diameter.

1. Side face of wheel, covering of a light fabric.
2. Edge of wheel.
3. Axle.
4. Two supports for the axle. The top plates suggest attachment to a ceiling.
5. Not found in picture. (Maybe it was the secret that makes it work!)
6. Four "stampers" (They move up and down to strike the box below).
7. Pegs on axle, to lift the stampers and release them.
8. Pendulum. One in front and one behind the wheel.
9. Linkage arm to drive the pendulum.
10. Linkage from axle to pendulum arm.
11. Weights on the ends of pendulum arms.
12. Pillars (to support the pendulum?)
13. Cross brace between pillars (?)
14. Peg to attach rope to axle.
15. Rope wrapped around axle.
16. Rope to lift weights.
17. Pulley attached to floor.
18. Rope (duplicate label?)
19. Wall, with open window.
20. Pulley outside window.
22. Weight being lifted.
23. Pulley support beam.
24 & 42. Brake lock attached to floor and wheel rim.

Bessler's drawings of his wheels are reasonably consistent with each other, and also consistent with eyewitness accounts. Certainly Bessler had no intention of giving away his secret in books, pamphlets or pictures, so this picture may have missing, misleading or incorrect details, and of course, whatever is inside the wheel is never shown. The scale of the sizes of parts may not be entirely consistent within the picture (even though a scale in els is shown at the bottom). Certain other details are a puzzlement.

  • The rope (16, 18) passes over two pulleys to the weight (22). This seems inefficient compared to a single rope segment and pulley.
  • Why does the rope segment (18) pass through the small hole in pillar (4)? With slight relocation of pulley (17) the necessity for a hole in the pillar could be avoided. Other diagrams also show this, more clearly.
  • The linkage (10, 9) from axle (3) to pendulum (8) seems to be only schematic. They appear flimsy, and the mechanical linkage is strange engineering. It is not clear whether the two pendulums were in phase or out of phase.
  • The function of the stampers seems only to provide motion and noise. The diagram indicates that the stampers and the pendulum were moving whenever the wheel turned. They could not be disengaged. Committees determined that that the stampers were not hollow, but don't say what they were made of or how much they weighed.
  • The rope passing from wheel axle to suspended weight outside the window may not indicate the true height of pulley (20), or the size of the window. The weight and this pulley are part of the edge view (mostly at the left), and the side view (right) is overlain over this by the artist. The second figure (below) shows this better.
  • We may suppose that pillars (4, 12, and 32) firmly fasten between floor and ceiling of a room. They are shown this way in some drawings (see figure below). But we probably should not therefore assume that the room is only about 13 feet from floor to ceiling. It might be greater than that, with the pillars shown as shorter by "artistic license".
  • Affidavits of the Merseberg demonstration (October 31, 1715) tell us that the demonstrations were repeated as many times as requested and that the 12 foot diameter wheel was removed from its supports and placed on another set of supports, presumably to demonstrate that power was not being supplied through the support bearings. Yet in Bessler's drawings, the construction does not seem to allow for easy removal of the wheel. The large wheel (illustration above) has been estimated to weigh 400 to 700 pounds. So it would require several strong men and block and tackle systems to remove this wheel and move it elsewhere.
  • Considering the weight of the wheel, these pillars (4) as shown in the drawing seem too insubstantial to provide the necessary support for the wheel, especially a moving wheel. However, one could argue that this structural weakness explains why pulley (17) is located near the pillar and directly below the axle, rather than going directly out a window to pulley (20).
The 12 foot diameter wheel lifting a weight, and the wheel with one of the pendulums.

Wheel data:

Since this information comes from English translations of the source materials, I have retained the English measurement equivalents. The source materials gave dimensions in ells, presumably the Flemish ell = 27 inches = 68.58 cm.

  • Wheel diameter, 12 ft.
  • Wheel thickness, 1 ft.
  • Axle length, 6 feet.
  • Axle diameter, 8 inches.
  • Iron bearing axle diameter, approximately 1 inch.
  • Wheel weight, 700 lb (317 kg mass), est.
  • Weights inside, 8 weights of 4 lb each. Total 32 lb.
  • Angular speed, unloaded, 26 rev/min.
  • Angular speed under load, 20 rev/min.
  • Time from rest to unloaded speed, 2 revolutions.
  • Pendulum length from fulcrum to weight, long arm, 9 ft. (est.)
  • Pendulum short arm length, from fulcrum to weight, 4.5 ft. (est.)
  • Natural period of pendulums, 2.35 sec. (est.) or 4 1/3 rev/sec. or 26 rev/min.
  • Weight (22) being lifted (a box of bricks), 35 lb,70 lb, estimated.
  • Distance weight was lifted, approx. 5 feet (1.5 m).

Speculations.

There's excellent agreement between the natural period of the pendulums and the unloaded speed of the wheel. This suggests that Bessler's own statement that the purpose of the pendulum was to regulate the wheel's speed may be taken as reasonable. Some have suggested that the pendulums drove the wheel (supplying continuous power to the wheel). I see no evidence to support that speculation. But these pendulums may have had a deceptive use, as we will see.

Could enough energy have been stored within the wheel itself to account for the reported demonstrations of its power? We have no certain details of what was in the wheel. Witnesses reported clanking and scraping sounds presumably from the eight 4 lb weights. The visible portion of the wheel was covered with opaque canvas fabric or oiled cloth, so no one could see the interior mechanism. No one ever reported seeing all of the eight weights said to be in the wheel. We have reports that a man who tried to stop the wheel by grabbing it at the rim was lifted off his feet, but generally no demonstrations derived any force or work from the rim of the wheel itself, only from the wheel's axle.

The visible impression the spectators got was of a massive 12 foot diameter wheel turning at 26 rev/min. Under load, it only slowed to 20 rev/min. That surely would seem impressive. How massive was the wheel? The contemporary documents don't tell us. One student of the Bessler story estimates 400 to 700 lb. Let's accept that as reasonable (for now) and see what we can conclude. We have no reason to suppose that anything but the wheel's outer shell rotated at that speed. Much of the weight inside the wheel may not have rotated at all. Surely the eight four pound weights were not the secret of the machine, for they could provide only 8 x 4 x 12 = 384 ft-lb of work even if they fell a distance of 12 feet, the diameter of the wheel. Lifting a 70 lb weight 40 feet requires 70 x 40 = 2800 ft-lb of work. Those cylindrical weights could only have been a distraction, a misdirection, to lead spectators to assume they were part of the secret of the wheels.

What people supposed
might be in the wheel.
An ancient idea.

Many witnesses concluded that the secret to the wheel's behavior must lie within the wheel itself. At this time many people were familiar with ideas for perpetual motion wheels, and many of these had moving weights inside. Of course, these wheels could only manage less than a revoluution before stopping. Observers heard clanking sounds as the wheel turned, and Bessler sometimes removed and then replaced a 4 pound metal cylinder through a small hole in the wheel's fabric covering. He was encouraging the hypothesis that the wheel was driven by weights inside. But, as we have seen, this may have been misdirection, for eight 4 pound weights clearly could not supply the work done by the wheel.

Suppose that 600 lb of weight inside the wheel was arranged to fall slowly, giving up its potential energy as it fell a distance of, say, 6 ft. That would provide 3600 ft-lb. One source says that the wheel lifted a 16 kg (35.274 lb) box of bricks 1.5 m (4.9 feet). That would require only about 75 ft-lb of work. Some sources say the bricks weighed twice as much, 70 lb, which would require only 150 ft-lb. This demonstration doesn't sound so impressive now, does it?

Diagrams suggest a box was raised from the courtyard outside a window, using a couple of pulleys. This might be a rise of 30 to 40 feet. A 30 foot lift of 70 lb of bricks would require 2100 ft-lb. That's still less than our hypothetical "weight inside the wheel" could supply. Also, there's the possibility that the box contained "fake" lightweight bricks.

Suppose the brick box weighed only 30 lb, it would require only 1200 ft-lb to raise it 40 ft. This would be only about a third of the maximum energy you could get from a falling weight inside the wheel. I find it curious that those who analyze the Bessler story have not questioned whether the fakery might be only partly in the wheel, but also in the manner in which the demonstrations were carefully staged. In all the accounts we have no clear statement of how many assistants Bessler required for these demonstrations. We know he had at least one. But surely the task of removing the 700 lb wheel from its supports and replacing it on different supports would require more than that. My suspicion is that his assistants were carefully instructed, just as a stage magician's assistants are as much responsible for the success of an illusion as is the actor who pretends to be a magician.

When the wheel was not lifting or doing other forms of work, the stored energy in the wheel and pendulums could maintain its motion for quite a while without drawing much energy from falling weight inside. The only energy loss would be due to bearing friction. The rate of fall of such a hypothetical weight could be varied, depending upon the work being done by the wheel. If no work was being done, the wheel presumably could turn for a very long time while the weight inside fell very, very slowly. The mechanism to accomplish that may have been the most important and ingenious secret Bessler wanted to keep.

Another speculation is that the wheel, or its rather unusually thick and long axle, contained a very tightly coiled spring to store energy for later release. The only suggestive piece of evidence for a spring that some critics cited is that Bessler was once "observed" to be making an adjustment through an opening in the canvas cover of the wheel and seemed to be "tightening" something. But this evidence is flimsy, for he certainly couldn't have been "winding" a spring by manpower to store 3600 ft-lb of energy! This observation could have other explanations and I don't give it much weight. But the possibility of a spring being wound prior to a public demonstration cannot be ruled out.

Bessler swore his wheel did not use "clockwork", falling weights (like a "grandfather" clock), or springs. We have only his word on that. In the demonstration at Kassel, where one of his large wheels ran 42 days supposedly without slowing, clockwork and a wound spring could easily accomplish that and even longer, assuming that it only had to rotate the lightweight outer frame of the wheel. This wheel was not required to do work or lifting demonstrations. If those earlier demonstrations requiring work were accomplished with slowly falling weight inside the wheel, those weights could easily have been disabled (or not present at all) in the Kassel demonstration, and a spring system used instead. There are no reports that that wheel did any demonstrations requiring it to do work, and no one saw the interior of that wheel.

I haven't read everything relating to Bessler. But I wish some Bessler scholars would clear up some points for me.

  • Were any of the demonstrations done out of doors? The demonstrations I've seen described were all done in interior rooms. How much more convincing they would have been if done in an open courtyard.
  • How many assistants did Bessler require for these demonstrations? Were they in his employ?
  • Did anyone weigh the bricks, or examine them closely? Did anyone other than Bessler or his assistants handle the bricks? Was their box ever even opened and the individual bricks removed for inspection? The historical accounts are silent on this point.
  • In the cases where the wheel was removed from its supports and replaced, just how was this done, considering that observers assumed the wheel to be quite heavy?
  • Did anyone ever weigh one of the wheels during a demonstration?
  • When the box of bricks was lifted several times, how was it lowered again to repeat the experiment? Could the lowering operation have supplied potential energy back to the wheel?

The Merseberg Demonstrations.

We will probably never know in detail how Bessler constructed his wheels. His own writings must be taken as self-serving, possibly engaging in misdirection. The eyewitness accounts are more interesting as sources of clues, though we must treat them with the same caution that we would treat the accounts of someone who had just watched the performance of an accomplished stage illusionist. If the performer is skillful, he has probably arranged things to encourage witnesses to assume things that weren't seen and weren't so. Bessler hid details of the mechanism of the trick, and used a knowledge of human psychology to deceive. I am reminded of the reports of witnesses at spiritualist seances of the late 19th century.

Those who wish to understand the methods of deception used in the 18th century would do well to look into the famous case of The Turk, a chess-playing automata constructed and exhibted in 1770 by the Austrian-Hungarian baron Wolfgang von Kempelen (17341804). It purported to be a machine designed to imitate a living being—an automaton. Automata were popular entertainment all over Europe in the 18th century, and exhibited a high degree of skill in construction. The Turk was an oriental figure seated before a chessboard on a cabinet in front of him. Doors in the cabinet were opened to reveal what appeared to be complex clockwork inside. The clockwork was wound up, and the Turk would play a game of chess with a human opponent, often winning. It was a hoax, for the cabinet, which observers swore they had seen to contain only clockwork, actually concealed a person, who manipulated the Turk from within. (The two cabinet doors were not opened simultaneously, so the hidden person had time to move out of sight behind the closed door—a very simple deception common in the large illusions of stage magicians.) I mention this example to remind readers that that century had an abundance of mechanical ingenuity sometimes combined with deception. I am not suggesting that any of Bessler's demonstrations were done with a person inside the wheels. The wheel's thickness would not accomodate even a small person.

Bessler's 11 foot diameter wheel was demonstrated to 12 dignitaries on October 31, 1715. They signed, attesting to, a document that has considerable detail. This is worth quoting because the details sound more imressive than those in accounts of other demonstrations of Bessler. But still there are many details inquiring minds want to know, that this document says nothing about.

The inventor first put in motion his six ells (~11 feet) in diameter and one foot thick machine which was still resting on the same wooden support upon which it had previously been mounted. It was stopped and restarted, turned left and right as many times as was requested by the commissaries or the spectators. The machine was started by a very light push with just two fingers and accelerated as one of the weights, hidden inside, began to fall. Gradually, within about one revolution, the machine acquired a powerful and even rotation, which continued until it was forcefully brought to a stop again; the machine preserved the same rapid motion when lifting a box filled with six whole bricks weighing together about 70 pounds. The weight was lifted by means of a rope conducted through a window by means of a pulley. The box was lifted as many times as was requested.

Furthermore the inventor, Orffyreus, in the presence of all, lifted the machine described above from its original wooden support. The timber posts were carefully examined from both top and bottom, as well as in the middle, particularly where a small cut was noticed. The same careful examination was devoted to the trunnions, the shaft, and to the bearings. During the inspection, not the slightest indication of imposture or deceit was found, rather everything was found to be right, complete, and without fault.

As further proof of its internal or inherent motive power, the machine was translocated to another support in such a way that the trunnions on both sides of the axle were laid uncovered in the open sockets. The whole assembly could see over and under, and both sides of the machine; and all present were invited to inspect the bearings, but no holes were found. All present examined them with their eyes, but no sign of fraud was seen. It was possible to translocate the machine and turn it left and right as many times as was asked by the respectable Commission. The machine regained its strong, fast, even rotation each time. The movement was accompanied by quite a loud noise that lasted until the machine was brought to a forced stop. Thus nothing suspicious happened.

Finally, it should be noted that right at the start, before the machine was subject to any testing, all rooms above, below, and on either side were examined by the Commission. It was also verified that the stamps were not hollow, and no indication of any mechanism moved by a cord was found.

All that has been written above is the truth, and has been acknowledged by signatures in our own hand without any reservations... signed at Merseberg, 31st October, year 1715.

This is one of the more complete attested accounts by witnesses. At first reading it sounds impressive because many details are given. Yet it is frustrating in what it does not tell us.

  • It doesn't tell the height the box of bricks was lifted. A height of 45 feet has been estimated from the supposition that the box was lifted from the ground in the courtyard up to the window.
  • There's no mention of anyone weighing the box of bricks. Just because they looked like bricks doesn't rule out the possibility that they might have been made of material much lighter than usual (pumice?), or have centers of straw.
  • It doesn't tell us the weight of the wheel.
  • It says that Bessler lifted the wheel from its supports and then placed it on different supports. How? With block and tackle, a jack, or a lever? Surely not all by himself.
Still, if we take this at face value as correct and complete, one is hard put to account for the details. This, and other, accounts seem to remove any suspicion from the wheel's supports. I can imagine that many students of the Bessler story have read and re-read these and still remained baffled. Some reached the conclusion that physical laws were being violated. But, I use the stage magician analogy again: Just because we can't figure out how a trick is done does not mean that it is really magic.

One mistake that we should not make is to assume that all of Bessler's wheels, and the various demonstrations of them, all used the very same methods of deception. Some things the smaller wheels could do may not have been done by the larger wheels in the same way. The wheel that "ran two months" in a sealed castle room was apparently never used to lift weights or do other forms of work. The earler demonstrations ran for short periods (how long, the accounts don't say). But none of the earlier wheels were reported to run for two months. So the various wheels may well have operated by different methods. Indeed some critics observed that the long-running wheel could easily have run by clockwork and a wound spring, even for much longer periods of time, since it was expending no energy other than that lost to friction. Nor should we assume that this wheel weighed as much as the others, for it could easily have been only a lightweight shell, since it was not required to do any heavy lifting. From the evidence, this demonstration seems quite unconvincing to me.

So we should not speak of Bessler's "wheel" but of Bessler's "wheels", for they may have been quite different in internal mechanisms, not only different in size. To use the singular suggests that they all operated on the same principles.

Weight of the wheels.

Contemporary descriptions of the wheels and accounts of the demonstrations do not tell us how much the wheels weighed. That's strange, for they repeatedly tell us other things like diameter, width, rotation rate, axle diameter, bearing diameter. Didn't anyone think the wheel weight was important? One student of the Bessler materials estimates that the larger wheels weighed 400 to 700 pounds, but doesn't say how he arrived at that figure. The account of the 1715 demonstration mentions that the wheel was moved from one set of supports to another during the demonstration. If the wheel did indeed weigh that much, we might assume that block and tackle, jacks or levers were used. Surely Bessler would not have taken the wheel apart to move the pieces in full view of spectators, for he took great pains to conceal what was inside the wheel.

What accounted for the wheel's weight? The visible portion was opaque canvas, oil-cloth or waxed linen on a lightweight wooden frame. We might generously assume the frame and axle accounted for 100 pounds. On at least one occasion a cylindrical metal weight was brought out from inside the wheel which an observer estimated to weigh four pounds. When the wheel rotated, eight "clunks" were heard per revolution, leading viewers to assume there were eight such weights inside, though only one had been seen. That's 64 pounds.

While eyewitness accounts give many other details, they are silent about the wheels' weight, or how that weight was measured. Why didn't they consider it important? You'd think they might at least mention how many men were required to lift it. It's an example of the fact that the witnesses, even those with scientific background, weren't considering the matter in a quantitative way. Even 's Gravensande, who did some calculations, first made the common (at the time) error of using mv for energy, rather than the correct mv2/2, an error he acknowledged later.

In the document above I've mentioned some of the problems with this story, and some of the hypotheses I've seen proposed. I am not saying that I accept any of these hypotheses. Many require assumptions for which we have no historical evidence, and probably never will have. But I see nothing in the accounts to suggest that anything magical, or even anything beyond presently known physical laws, was going on. Those who want to believe that Bessler's wheel was an over-unity device assert with confidence "The evidence shows there was no possibility of fraud." On the contrary, as I read the evidence, it shows many possibilities for fraud, and strongly suggests that Bessler was a clever deceiver.

People ask me why I find this historical cold-case somewhat interesting, supposing that I might harbor the suspicion that Bessler's wheels really violated physical laws. Not at all. I have long been interested in conmen who cleverly deceive people: artists who fool the experts with forged paintings, writers who invent hoaxes. They serve a valuable social purpose, teaching us to look behind appearances, mistrust our emotions, hopes and beliefs, and to recognize what's possible and what isn't. Anyone who could fool people not only in his lifetime, but centuries after his death, as Bessler did, certainly deserves recognition.

  • Donald E. Simanek, April 2004, revisions 2007, ...2012.

Return to perpetual futility.